Telegraphy.



G. 0. SQUEERt TELEGRAPHY.

` APPLICATION min JuNEza; 1915.

Patented July?, 1917.

PATENT OFFICE.

enoncn ownn semina, voi Marsala, Lennon, ENGLAND.

. TELEGRAPHY.

' followin is a speciication.

This i vention relates to telegraphy and more esfiecially to submarine cable telegraphy and; provides an improved system of transmission intended to overcome the disadvantages due to the customary method of signaling, and openedfor naling impulse. .According to my invention the messages are transmitted by an unbroken alternating current` the amplitude of Whose Waves is varied to produce the signaling impulses. The signaling unit may be a half Wave length (all signals being of equal length) and the transmitting apparatus is so arranged that the impulses are timed in accordance With the Wave length. For the transmission of the dashes, dots and spaces of the usual cable code three different Wave amplitudes Would be employed, for example, a Wave of large amplitude for a dash, of medium amplitude for a dot and of smaller amplitude for a space.

The variation in' amplitudeis conventhe transmission of a sigiently veffected by' introducing variations each member bringing in or into the transmitting or cable circuit by or imped'ances.`

means usually of resistances For this purpose a resistance or impedance element, which may be adjustable, is connected between the end ofthe cable (at the apex of the bridge in the duplex` system)' or the primary of a. transmitting transformer and the current generator, While a shunt circuit passes through the transmitter, by means ofivhich either a part or the Whole of the resistance or impedance may be shunted. Three different wave amplitudes are thus produced, a relatively7 small amplitude representing, say, the spaces when the complete resistance or impedance is in the circuit, a moderate amplitude for the dots When part of the'resistance or impedanceis shunted, and a large amplitude for the dashes When the complete resistance `or impedance is shunted. Three contact members might of course be employed to give a siinilaitresult, shunting its own resistance.

l Speccation of Letters Patent.

in `Which the circuit is closed `transformer-windings,

Patented July 17, 1917.

Application lled J une 25, 1915. Serial No. 36,400.

As the phase angle between 'the impressed` E. M. and the resultant current'in the transmitting circuit is altered by the introduction of the various resistances or im pedances the contact members of the trans-- mitter are made adjustable longitudinally -of thev tape and .one is displaced relatively to the other to such an extent as to compensate for the alteration in phase angle due to the change in resistance or impedance.

Shunting' thewhole or part or a resistance onimpedance is given as. a suitable method of varyingthe amplitude of the cable current, but it is obvious that other methods are possible, such, for example, as

shunting or cutting out part of the pri-I or secondary of the transmitting transformer if one is used, or varying 1n any convenient manner the inductance of the transmitting circuit.

In order that my inventionmay loe more clearly effect, I Will describe the same lmore fully understood and readily carried into with reference to the accompanying draws ings, in Which-h Figure n rangement of circuits and operating parts at. thetransmitting and receivirrgtends lof a cableto which our improved s em is applied. v

Figs. 1a and 1b` show two slight modifications o the transmitting end ofthe cable.

Figsllc and 1d show a portion of the s stem of Fig. 1, modified to introduce in the contacts for varying the current in the transmitting circuit, and, therefore, the amplitude of the waves.

Fig. 2 shows a portion of a punched tape suitablefor transmitting/in this system.

Fig. 3' shows the ave form of the current produced'in t e cable by the aid of the portion `of tape/.shown in Fig. 2, the form illustrated giving the beginning of the alphabet according to the Morse code.

Fig. l is a/ liagram of a relay and printer which may/,fe provided at the receiving end of the cable, and

1 is a diagram of the general arl nected to earth at each end through lthe secv ondary I) of a transmitting transformer B the primary b" of which is in a transmitting circuit C containing the alternator c and the resistance c (shown as an inductive receiving end or the cable.

sistance in Fig. l) employed for varying the amplitude of the current impulses in the transformer and impressed on the cable.

ting tape. E E are the erated by the tape.

D is the transmitcontact levers op- F is a relay at the re- G is the printer. H 1s the receiving tape or slip.

A. The tape D is intended to be fed at a constant rate by the usual star wheel actin through the central row of holes d the movement of the tape synchronizing with the alternator c. The messages are to be transmitted by the perfor-ations d', d2 on each side of the holes d, the perforations al' and d2 servin respectively for dots and dashes of the orse code. Thefshort perforations are for single impulses (either dot or dash according to the row d or d2) and i ate contact arms K in the longer perforations are for two or more successive impulses of the same signication.

A transmitting apparatus of pecker type is shown in Fig. 1, the two levers- E, one for each of the two rows of perforations d', d2, carrying peckers e pivoted at e and provided with sprin s e2 tending to draw them against the adgustable contacts J in the relay circuits j, which circuits operthe electromagnet circuits c, the electromagnets k of which con trol the levers E. tration the levers E and associated parts are shown displaced longitudinally in the o diagram, but in practice the levers are placed side by side and turn about the same axis es.

he levers are under the control of thc springs e4 which keep the peckers e up against the tape and cause them to project through the perforations d or d2 as the latter pass over the packers. The levers E each carry a contact arm e connected to the cable end of the resistance c and adapted t0 meet the contacts c2, c", connected re- `b spectively to the middle and the alternator ei. of the resistance.

"lh general operation of the transmitting mechanism is as follows:-

As the ."ne D passes over the two peckers e immediate. one of the perforations d' or d2 meets the end of a pecker the latter is released and the spring epulls down its end of the lever, the pecker passing through the tape perforation and the contact' arm e meeting the contact c2 or c (Figs. lor 1b), short circuiting either a part or the whole of the resistance c. The short-circuiting action continues until the rear end of the tape aperture meets the pecker, when continued movement' of the tape pushes the end of the-Hecker forward around its pivot e and against-the spring e2, breaking the relay circuit j at the contact J. The relay circuit j is normally closed and holds the contact arm K open so that the branch electromagnet circuit is normally open and consequently the E. M. F.-

magnet circuit 7c For purposes of illus.

the electromagnet uneXcited, the pressure of the pecker e against the under side of the tape holding the lever E against the spring et. The action of the relay is practically instantaneous, as the moment the circuit j is broken the switch arm K returns to close the electrgmagnet circuit v7|: and excite the electromaget t so as to raise the end of the lever\E against the spring e* and open the shunt circuit at the contact c2 or c", the pecker by the same action being withdrawn from the tape aperture. The withdrawal of the pecker allows the sprin e2 to Iull it back against the contact J an close he relay circuit j again, breaking the electro- (which is of lower resistance than the circuit j) and releasing the arm E"ready for the next`pecker operation.

The apertures d', d2 are ofsuch a length that the shunting of the resistance o occupies exactly a complete half Wave period of the alternator or a multiple thereof and the length of an aperture is measured by the distance traveled by the tape ia such a space of time, plus the diameter of the end of the 'ecker, and such correction as may be required by the movements of 'the pecker.

he apertures therefore somewhat overlap as shown in Fig. 2. In order that the shunt-` lng of the resistance or impedance c' may occur 'exactly in phase with the current a relative longitudinal adjustment of 'the two lcontact devices for the perforations d', d2 is provided. The` phase angle between the E F. and current in the transmitting circuitvwill dier slightly according' to whether the full resistance c, part resistance or no resistance is inserted in the circuit. The perforations d', d2 might be displaced to give an approximate correction for constant resistance conditions but I prefer to mount the contacts J on "adjusting screws j so that y adjusting one contact forwardly or backwardlv relatively to the other the diiierence in phase may be accurately compensated and the transmission of complete half wave impulses insured.

Instead of connecting the contacts c2, c? to points on the resistance or impedance c as in4 Figs. 1a and l" they ay be connected, as shown in Fig. l, to blints y, y on the transformer primary b, or alternatively to o'ints y, ys on the secondary b as shown in ig. ld, shunting lor cutting out more or less of the transformer coil. If the secondary coil b is employed for this purpose the contact arm e5 of the lever E would be connected to the secondary at '3/4 instead of to the transmitting circuit C. In Fig. 1 a slight modification is shown in which thek transformer B is dispensed with and one 'pole of the alternator c connected directly to the cable through the resistance c. The other pole of the alternator is earthed. The method of sending the mes- `The wave form represents,

' sages is the same as in the apparatus already described.

In Fig. lbthe alternator c is connected to an earthed auto-transformer B', to any suitable point of which the end of the cablel is also connected. This arrangement possesses some advantages as it allows of ready adjustment of 'the E. M. F. impressed on the cable and also allows of the resistance c being somewhat reduced as compared with that necessary in the arrangement employing the ordinary transformer.

According to Figs. 1c and 1d, adjustment of the E. M. F. is effected by regulating the number of. coils that remain active in the primary or secondary of thetransformer.

The resulting wave form of the current 1n the transmitting circuit and the E. M. F.

impressed upon'the cable is shown in Fig.4 3 for the transmission of the first four let= ters of the alphabet, above the wave form being the corresponding tape perforations shown in Fig. 2. The smaller' impulses w represent the spaces in the Morse code,'the medium impulses w' represent the dots and the large impulses wz the dashes, the impulses and :U2 belonging respectively to the perforations d and d2 of the tape D. therefore, a dot and a dash for A, adash and three dots for B, dash-dot-dash-dot for C and dash-dotdot for D, corresponding to the perforations in Fig. 2 above. The spaces between the letters are marked S. Each impulse or half wave is' of sine form, the only difference in 'the impulses residing in their amplitude.

Dealing now with the reception of the messages the relay F is connected across the cable and artificial line. Any suitable relay may be. employed but l prefer to use a modiication of the Muirhead gold wire relay in i which the gold wire f (Fig. 4) when curther apart than the posts leo rent passesthrough the relay, turns around the fixed end f and makes contact between either of the small platinum posts f2 connected through a-resistance f3 to a local wire relay F, a second pair of posts j, set farfg, also being connected to the relay F, which controls the printer through the arm f5. The second relay F is introduced as the gold wire-relay is somewhat delicate for the direct voperation of the printer G. The arm f ismove against the contact g belonging 'to rthe printer when the gold Wire f of the relay F is brought against one of the rst posts 2 while the posts f* are sov placed that a very small additional movement of the wire f, after meeting one of the posts f2, causes slight bending of the wire at f2 so that it also meets the post f* at the same side and causes a further movement pf the arm f3 through the relay F so as to bring it against the second contact g controlling the printer.

the signal impulses.

The posts f2, f* correspond to the dots and dashes of the code and a convenient methwl of recording is to provide a printer. having two light printing arms g2, gs arranged. to mark like a siphon recorder, one arm having a central marking tip gr4 while the other has a forked tip g5, an electromagnet g belonging to the former arm being connected tothe contact g while the other electro- 5, in which a central line of marks h belon the arm g2 altape is therefore of the form shown in both to dots and dashes and the dashes a distinguished by bringing in the side marks It made by the forked arm g3. The smaller impulses a: transmitted by the cable are just too small to move the gold wire into contact with the posts f2, while the medium impulses af are large enough to move the wire against these posts without further action and the large impulses m2 are suiiciently strong to give the wire a larger movement and bring it into contact with one or other ofthe posts ft. Thus the impulses m and m2 represented in Fig. 3 are recorded by the marks h, h on the tape H and can be read with great ease. It is to be understood, of course, that the relay and printing device form only one means out of many by which the messages may be received. y

rl`he present system of telegraphy allows of repunching tape or interpolation without the provision of any special synchronizing mechanism. As an unbroken alternating current is sent through the cable much higher voltages can possible in existing systems and a substantial amount of power can be transmitted.

be employed than isl Since the transmission of messages depends space and signal impulses the space impulsescan be of considerable r`strength provided such margin is allowed.for and the uninterrupted alternating current canbe used to drive, through a vsuitable relay, a retransmit-` ting slip apparatus while the slip can be punched by the aid of relays. operated by Since the alternating currentitself controls the sending on device synclironism is obtained automatically. The apparatus is merely an adaptation of apparatus of well known type. I

With regard to the general principles on which this system is based it is well understood that the most etlicient method of transmission over a submarine cable would be an uninterrupted alternating current of simple 1s in the amplitude of the waves, each signaling time. i

It will be seenthat since an uninterrupted alternating current is employed consecutive impulses are necessarily in opposite directions, although of different amplitude, this insuring a lcondition generally recognized as desirable in cable telegraphy. Much higher voltages than is customary can be safely employed since there is no danger of sending a current of substantial duration in one direction.

, ferred arrangement) thus alternating current of a waves of the said One of the chief advantages attained is the more perfect balancing by the artificial line which is rendered possible by the use of unbroken sine Waves. The breakage of the cable circuit by the usual transmitting method causes a sudden kick which cannot be effectively balanced and affects the reception of messages, while such disturbances are eliminated by the smooth variable curve representing the current on the new system. Better balancing allows of higher speed of duplex transmission so that the value of the cable is increased. The employment of the alternating current moreover enables me to utilize the standard forms of electrical measuring instruments for determinating the behavior of the plant, in the same manner as they are at present employed in power transmission.

The cable circuit is permanently connected to earth at each end (through the low resistance coil of a transformer in the preproviding a permanent drain to earth.

While the present system is of special utility in submarine cable Work it is also applicable to land lines. The system may thus be made a universal one with interchange` ability between land and cable work.

What I claim and desire to secure by Letters Patent of the United States is 1. A method of sending telegraphic messages through a line which consists in trans" mitting through the linel an uninterrupted:

single low frequency and Ain varying the amplitude of the current so that they individually represent dots, dashes and spaces as different signaling impulses.

2. A method of sending telegraphic messages through a line which consists in transmitting through the line an uninterrupted alternating current of asingle low frequency and in varying the amplitude of each half element occupying the same unit of\ Wave of the said current to dash pulse.

8. A. method of sending telegraphic messages through a line which consists in transmitting an uninterrupted low frequency alternating current, and varying in three stages the amplitude of the individual Waves of the said current, so that they produce impulses, individually representing spaces, dots and dashes.

4. A method of sending telegraphic messages through a line which consists in transmitting an uninterrupted low frequency alternating current and vin altering the resistance of the transmitting circuitin synchronism with the individual waves of the said current so as to produce signaling impulses.

5. In a system of line telegraphy, means for transmitting a single uninterrupted low frequency alternating current through the line circuit,

produce a dot, or space as a different signaling imwaves of the said c ent which shunts the said resistance in sections so as to vary the amplitude of the individual Waves Without opening the circuit.

' 6. In a system of telegraphy, a circuit, means for producing in said circuit, an unbroken alternating current, and means for sending over said line the three elements of the alphabet, namely, dots, dashes and spaces by complete semi-cycles of said current; said last-named means includinvr means which vary the amplitude of the waves of said current in synchronism with the alternations of the current and thereby distinguish the signals.

7 In a system of line telegraphy, means for producing an uninterrupted alternating current in the transmitting circuit, means for introducing variations into the said circuit to produce signaling impulses without opening said circuit, an automatic transmitter controlling the said variations and adjusting means in the transmitter adapted to vadjust the timing of the variations relative to the individual waves of the current so as to compensate for changes in the phase angle between the E. M. F. and resultant current due to variations in the circuit.

8. In a system of line telegraphy, means for producing an uninterrupted alternating current in the transmitting circuit, means for introducing variations into the said circuit without opening the circuit, a tape transmitter having dot and dash perforations and operated in synchronism with the alternations of the current, members actuated by the dot and dash perforations of the tape for controlling the circuit varying means, and means for relatively adjusting the said members longitudinally of the tape.

9. In a system of line telegraphy, means for producing an uninterrupted alternating current in the transmitting circuit, means for introducing variations into the said circuit Without opening the circuit, a perforated tape transmitter operated in synchro nism With the alternations of the current, pecker mechanism adapted to control the .circuit varying means and including pecker arms adapted to pass through the tape perforations and adjusting means for the pecker mechanism adapted to adjust the timin yof the variations relative to the indivi ual Waves of the current so as to compensate for differences of phase angle in the transmitting circuit due to the variations in the said circuit.

10. In a system ofline telegraphy, means for producing an uninterrupted alternating current in the transmitting circuit, means for` introducing variations into the said circuit without opening the circuit, a perforated tape transmitter operated in synchro nism with the alternations of the current, pecker mechanism adapted to control the circuit varying means and including pecker arms adapted to pass through the tape per- Jorations, contacts met by the said pecker arms for circuit controlling purposes, and means for adjusting the relative positions of the said contacts.

11. In a system of telegraphy, an alternator continuously connected in the transmitting circuit and means for introducing variations in the said circuit to change the amplitude ofthe individual alternations so that each semi-,cycle corresponds to a dierent signaling impulse without opening the circuit.l

GEORGE OWEN SQUIER. 

